ValueTracking: Restore ordered negative handling for frem

[arsenm]

Summary

In D148674, the negative condition was weakened to only
checking isKnownNever(fcNegative), instead of cannotBeOrderedLessThanZero().

This avoids a regression when CannotBeOrderedLessThanZero is
replaced with computeKnownFPClass.

[arsenm]

Same should also be done for fdiv but I guess there weren't any pre-existing tests relying on this

[kpn]

LGTM

[arsenm]

0ee2245ab2232e454151e5c9d1637cde4686ee9c

llvm/lib/Analysis/ValueTracking.cpp

if (Op->getOpcode() == Instruction::FDiv) {
       // Inf REM x and x REM 0 produce NaN.
       if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
           KnownLHS.isKnownNeverInfinity() &&
           KnownRHS.isKnownNeverLogicalZero(*F, Op->getType())) {
         Known.knownNot(fcNan);
       }
 
       // The sign for frem is the same as the first operand.
+      if (KnownLHS.cannotBeOrderedLessThanZero())
+        Known.knownNot(KnownFPClass::OrderedLessThanZeroMask);
+      if (KnownLHS.cannotBeOrderedGreaterThanZero())
+        Known.knownNot(KnownFPClass::OrderedGreaterThanZeroMask);
+
+      // See if we can be more aggressive about the sign of 0.
       if (KnownLHS.isKnownNever(fcNegative))
         Known.knownNot(fcNegative);
       if (KnownLHS.isKnownNever(fcPositive))
         Known.knownNot(fcPositive);
     }
 
     break;
   }

llvm/test/Transforms/Attributor/nofpclass-frem.ll

 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG]], [[ARG]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg, %arg
   ret float %frem
 }
 
 define float @ret_frem_no_neg_lhs(float nofpclass(ninf nsub nnorm) %arg0, float %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg_lhs
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg_lhs
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 

 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 
 define float @ret_frem_no_neg(float nofpclass(ninf nsub nnorm) %arg0, float nofpclass(ninf nsub nnorm) %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float nofpclass(ninf nsub nnorm) [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 
 define float @ret_frem_no_neg_nzero(float nofpclass(ninf nsub nnorm nzero) %arg0, float nofpclass(ninf nsub nnorm nzero) %arg1) #0 {
 ; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_frem_no_neg_nzero
 ; CHECK-SAME: (float nofpclass(ninf nzero nsub nnorm) [[ARG0:%.*]], float nofpclass(ninf nzero nsub nnorm) [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 
 define float @ret_frem_no_neg_rhs_no_nzero(float nofpclass(ninf nsub nnorm) %arg0, float nofpclass(ninf nsub nnorm nzero) %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_neg_rhs_no_nzero
+; CHECK-LABEL: define nofpclass(ninf nsub nnorm) float @ret_frem_no_neg_rhs_no_nzero
 ; CHECK-SAME: (float nofpclass(ninf nsub nnorm) [[ARG0:%.*]], float nofpclass(ninf nzero nsub nnorm) [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 

 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }
 
 define float @ret_frem_no_pos_zero_lhs(float nofpclass(pinf psub pnorm) %arg0, float %arg1) #0 {
-; CHECK-LABEL: define float @ret_frem_no_pos_zero_lhs
+; CHECK-LABEL: define nofpclass(pinf psub pnorm) float @ret_frem_no_pos_zero_lhs
 ; CHECK-SAME: (float nofpclass(pinf psub pnorm) [[ARG0:%.*]], float [[ARG1:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:    [[FREM:%.*]] = frem float [[ARG0]], [[ARG1]]
 ; CHECK-NEXT:    ret float [[FREM]]
 ;
   %frem = frem float %arg0, %arg1
   ret float %frem
 }